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Rotational Spectra of Four of the Five Conformers of 1-Pentene
Published
Author(s)
Gerald T. Fraser, L H. Xu, R D. Suenram, C Lugez
Abstract
The rotational spectra of four of the five expected conformers of 1-pentene, together with their monosubstituted 13C isotopic forms, have been measured in a molecular beam using a pulsed-nozzle Fourier-transform microwave spectrometer. One of the conformers has Cs point-group symmetry while the other three conformers have C1 point-group symmetry. The measurements are compared to results from molecular modeling calculations using the MM3 molecular-mechanics force field of Allinger et al. and to ab initio electronic structure calculations (MP2/6-31G*, MP2/6-311G*, MP4/6-31G*, MP4/6-311G*). Both types of calculations suggest the existence of five distinct conformers of 1-pentene, 4 of C1 symmetry and 1 of Cs symmetry. Both the MM3 and ab initio rotational constants deviate from the measured values by {less then or equal to} 5 %. The relatively high barriers between the four conformers limit the conformational cooling in the expansion, allowing all four conformers to be observed at the
Fraser, G.
, Xu, L.
, Suenram, R.
and Lugez, C.
(2000),
Rotational Spectra of Four of the Five Conformers of 1-Pentene, Journal of Chemical Physics
(Accessed December 2, 2023)